1. Field of the Invention
This invention relates to seed planting machines and in particular to an improved potato planter that is adapted to deposit seeds in one or more furrows with precision at high ground speed in several furrows simultaneously.
2. Description of the Prior Art
Various forms of potato seed planters have been proposed in the prior art. Typically, a prior art potato seed planter is drawn over the ground by a tractor, a plow attached to the planter opening a furrow or crop row into which seeds are dropped by a plurality of circulating planting devices or elevators provided with pick-up elements or cups from a seed receptacle or hopper. In one such form of potato planter, as illustrated in German Pat. No. 565,279, issued on Nov. 28, 1932, parallel seed belts arranged side by side dispense seeds to the same furrow by attached cups. Such a parallel arrangement is desirable in that it allows the cups to move through the hopper at a lower speed for the same ground speed compared with planters equipped with a single belt only thereby enabling more careful treatment of the seeds in the hopper. Such planters have the disadvantage, however, that due to the configuration of the cups the seeds are allowed to drop essentially unguided into the furrow as a result of which planting is irregular. The seeds fall on the flanks of the furrow from where they fall down haphazardly and as a result do not come to rest in a straight line, nor are they spaced uniformly in their rest positions.
Potato plants have also been proposed which are adjustable to vary the spacing between crop rows by the inclusion of size adjustable seed receptacles, or hoppers, mounted on a wheeled frame. As illustrated in U.S. Pat. No. 3,683,829, W. S. Herrett, the spacing of the hoppers and the planting mechanisms carried thereon relative to one another are adjustable to various crop row spacings by sets of mutually adjacent sloping bottom walls of mutually adjacent hoppers which are freely straddled by a ridge plate in slidable relation thereon. Such an arrangement although workable for adjustment of the size of the receptacle or hopper, is difficult to operate due to high fraction forces present between the sliding plates.
Potato planter proposals have been made also concerning other aspects of the planting. In particular, wheeled frames upon which receptacles and circulating planting devices or elevators are supported while planting, as illustrated in U.S. Pat. Nos. 3,322,428, C. M. Cooley and 3,132,610, C. C. Hoffman, include additional, flexibly attached frames upon which seed hoppers and planting mechanisms are mounted so that many crop rows can be planted simultaneously. Such arrangements although adjustable to plant under various ground conditions are incapable of maintaining the planting depth relatively constant under uneven ground conditions without the inclusion of complicated structure involving many connected parts.